- * hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses
- * @range: range being snapshotted
- * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid
- * vma permission, 0 success
+ * hmm_range_snapshot() - snapshot CPU page table for a range
+ * @range: range
+ * Returns: number of valid pages in range->pfns[] (from range start
+ * address). This may be zero. If the return value is negative,
+ * then one of the following values may be returned:
+ *
+ * -EINVAL invalid arguments or mm or virtual address are in an
+ * invalid vma (ie either hugetlbfs or device file vma).
+ * -EPERM For example, asking for write, when the range is
+ * read-only
+ * -EAGAIN Caller needs to retry
+ * -EFAULT Either no valid vma exists for this range, or it is
+ * illegal to access the range